Traditional motor vehicle ignition locks include a barrel connected to an ignition switch, a stationary sleeve around the barrel, and a side bar on the barrel which projects into a slot in the sleeve to prevent rotation of the barrel. Such traditional locks are mechanically unlocked by a key inserted in a slot in the barrel. The key aligns tumblers in the barrel which, when aligned, permit springs in the barrel to retract the side bar into the barrel. With the side bar retracted, the barrel is rotatable in the sleeve to actuate the ignition switch.
Ignition locks having various electronic unlocking modes have also been proposed. In one example, a lock barrel controlling an ignition switch is immobilized by a solenoid plunger which is withdrawn when an electronically coded key is inserted in a slot in the barrel. In another example, an ignition switch is immobilized by a blocker which is withdrawn from a blocking position by a solenoid in response to a coded signal transmitted from a remote device, such as a remote door lock operator, to permit keyless actuation of the ignition switch.
Also, a lock having mechanical and electronic unlocking modes has been proposed in which both a key and a coded electronic signal are required for unlocking. That lock includes a key controlled barrel like a traditional lock and a solenoid operated plunger like an electronic lock which plunger blocks rotation of a barrel until a coded signal is received, even if the key is in the barrel.
An ignition lock according to this invention has independent electronic and mechanical unlocking modes.